danger/u/
Maintaining 12v off a battery for an inverter (do batteries count as /tech/?)

| Hey tech, so i live in my rig and i have a solar system with a couple of sealed lead acid batteries and an inverter for my laptop.
Problem is, if im playing a game or basically ever running the fans on the laptop and the battery voltage is below something like 12.5 the inverter shuts down. I get that the inverter isnt getting enough voltage to keep up with the watt requirements, so is there a way to keep the voltage above 12.5 for the whole discharge? Or is that a bad idea?


| >>730192
Also i was thinking about it and as far as i know a laptop charger takes 110 and drops it to 19v, so in my rig its going
12v->110v->19v
Would it be better to install some kind of step up so i can go straight from 12v to 19v instead of the inverter in the middle? Or am i likely to fry something cuz of some arcane secret in the charger


| there should not be any problems going straight 12v-19v and it will be more efficent, just be carefull to get something that's actually consistently 19v


| also if i understand correctly you're trying to discharge the entire voltage? that will break the battery


| >>730427
Well obviously discharging everything at once would break it, but i mean keeping the output voltage at around 12.5 the entire time the battery is discharging instead of the voltage lowering as the charge lessens. Im pretty sure thats a thing but i cant find anything online about it, maybe just because i dont know the actual term for something like that


| The normal setup for something like this is a boost converted with seperate over discharge protection circuit. while this is likely to improve efficency. you have to understand that
-depleating the battery under 10V will break it
-discharging batteries _always_ decreases their voltage
it's why you need over discharge protection

i doubt you have enough batteries to actually run a pc for any resonable duration.
so get more and/or build a pc especially for power efficency


| >>730732
Okay, relly good to know actually, thanks for the help! I think ill get a couple more cheap lead acids and maybe have them as a dedicated laptop bank for now. The (3rd) worst thing about being homeless has been being unable to play vidya all night, so im trying whatever solutions i can find


| >>730829
10V was a avrage/ semi-random estimate, it depends on battery. it doesnt nececerally break immeadiatly just might prolong the charge time from a hour too a day or two (all of this being dependent on the battery), that's about all i know on the topic, good luck!


| https://en.wikipedia.org/wiki/Charge_pump


| >>731017
neat didn't know those ware a thing but reading about it their only good for up to half a amp, no?


| >>731042
You have to calculate the correct dimensions for the capacitors and diodes ofc. You may also have a look at the "see also" section in the article. I once used such a circuit for a 15W device. How much does your laptop take?


| I've been in your position, going from 12v to 19v gets you waaay more time out of your batteries than going through an inverter.

Look for a 'car charger' or 'lighter socket charger' for your model laptop. These can be weirdly expensive though, it's often way cheaper to get a generic 'universal' car charger, set it to the right voltage & if it doesn't fit your laptop solder the end of a regular charge cable to it.

Good luck out there guurl!


| Also, the inverter shuts down at 12.5 to save the batteries, as discharging below ~12v will permanently reduce their capacity.
You should be overcharging your batteries instead - they'll be healthier going from 13.5v to 12.5v than they would 12.5v to 11.5v.
I've gone as high as 14.5v before, but anything past that and you risk boiling the acid and probably gassing yourself to death in the back of your rig.


| Can't you just idle your engine? Emptying your battery is playing with fire, if you can modify your rig, just get a tripac or something


| >>731380
Best answer of the thread
I was just looking at some of these they look perfect, only problem is that the laptop draws 135W and the biggest one i could find was i think 120W? Which should be okay, right? If i just keep settings to a minimum to keep the fan from jumping up it aught to charge the same i think?
>>731540
I could idle to charge the batteries then plug in the laptop, but running it while charging the comp gets weird, i think because of how the alternator charges

Total number of posts: 15, last modified on: Wed Jan 1 00:00:00 1611022369

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